1. Field of the Invention
The present invention relates to a fuel cell system, and more particularly, to a fuel cell system using a liquefied gas such as butane and a method of driving the fuel cell system.
2. Description of the Related Technology
As is well known, a fuel cell is an apparatus that generates electrical energy by using a fuel and an oxidizing gas. Fuel cells are mainly classified as polymer electrolyte membrane fuel cells and direct oxidization membrane fuel cells. A fuel cell system using the polymer electrolyte membrane fuel cell includes, among other things, i) a stack constructed by sequentially stacking a plurality of fuel cells, ii) a reformer that reforms a fuel to generate a reforming gas, iii) a fuel supply unit that supplies the fuel to the reformer, and iv) an oxidizing gas supply unit that supplies an oxidizing gas to the stack. When the fuel is supplied to the reformer, the reformer reforms the fuel to generate the reforming gas. When the reforming gas and the oxidizing gas are supplied to the stack, the stack generates electric energy through an electro-chemical reaction of the reforming gas and the oxidizing gas.
During the driving of the fuel cell system, the stack generates heat through a reduction reaction of the oxidizing gas, and the reformer also generates heat through a preferential CO oxidation (PROX) reaction for reducing a concentration of carbon monoxide contained in the reforming gas. The stack and reformer are cooled by an air-cooling unit or a water-cooling unit, so that the stack and reformer can be maintained at suitable operation temperatures.